JP4254906B2 - Highly reflective paint and painted metal plate - Google Patents

Description

  The present invention relates to a coated metal plate having a highly reflective paint and a highly reflective coating formed from the paint, and mainly used as a reflector of a lighting fixture.

  There is a need to improve the efficiency of lighting fixtures from the viewpoint of energy saving. Conventionally, the efficiency of appliances has been improved by improving the luminous efficiency of light sources (fluorescent lamps, mercury lamps, incandescent lamps, etc.). However, in recent years, further improvement in appliance efficiency has been demanded, and improvement in reflectivity has been strongly demanded for reflectors of lighting fixtures. This is because if the reflectivity of the reflector is improved, the light from the same bulb or fluorescent lamp can be felt brighter.

  Patent Document 1 discloses a technique related to a thin white precoated steel sheet. This is for developing a high white color (high reflectivity) even in a thin film, and has a base treatment layer containing an organic resin and titanium oxide as a white pigment and tannin or tannic acid at the same time. The present invention relates to a precoated steel sheet having a coating layer containing titanium oxide as a white pigment.

According to this technique, the whiteness (reflectivity) is improved by increasing the amount of titanium oxide in the coating film or increasing the film thickness to some extent. However, since the reflectivity is increased uniformly over the entire wavelength range, there is a limit to the improvement in reflectivity, and when used in a reflector of a lighting fixture, the reflectivity improvement effect can be realized as if the brightness has increased. There is a problem that it is difficult to obtain, or that it causes deterioration of other characteristics.
Japanese Patent Application Laid-Open No. 2000-2127767

  INDUSTRIAL APPLICABILITY The present invention provides a coated metal plate suitable as a reflector for a lighting fixture that can efficiently improve the reflectivity at a wavelength at which the visibility reaches a peak by using the visibility characteristics of the human eye, and is used for the coated metal plate. It is an object to provide a paint.

  The wavelength range (visible range) perceived by the human eye is 380 to 780 nm. However, even if the energy is equal for each wavelength within the range, it does not feel the same brightness. The brightness is barely felt from around 385 nm, and gradually increases to reach the maximum at 555 nm, and then gradually decreases and disappears around 765 nm. The degree of feeling such brightness is called visibility.

  The present inventors pay attention to this visibility, and in order to efficiently improve the reflectivity as a reflector of a lighting fixture, it is necessary to convert incident light as close as possible to the peak of visibility at 555 nm and reflect it. I realized it was good. By doing so, it becomes possible to make the reflected light of the same energy feel brightest.

  In order to realize such reflection performance, a film may be formed by applying a paint using a fluorescent pigment having a light emission characteristic (peak of emission spectrum) in the vicinity of 555 nm. As a result, the fluorescent pigment absorbs incident light with a shorter wavelength and lower visibility, converts it into light near 555 nm, and emits it as reflected light. It is also possible to form a film that exceeds 100%.

  On the other hand, when the light source is a fluorescent lamp, a spectrum having an extremely high intensity due to mercury rays (g-rays) is irradiated in the wavelength range of 430 to 440 nm. Because this mercury ray has a small wavelength, it is difficult for the human eye to recognize it as bright (low visibility) for the reasons described above, but it has a large energy, so this wavelength If the peak can be converted to around 555 nm, the reflectivity can be improved efficiently.

  In order to realize such reflection performance, a film may be formed by applying a paint using a fluorescent pigment having excitation characteristics (excitation spectrum peak) in the vicinity of 430 to 440 nm. As a result, the fluorescent pigment absorbs a large amount of energy resulting from mercury rays and emits fluorescence. Fluorescence has a wavelength longer than the wavelength of the excitation spectrum according to Stokes' law, and thus the visibility is close to the peak of 555 nm, so that reflected light having higher visibility than the mercury ray that is the excitation light can be emitted, thus improving efficiency. Well, the surface reflectivity can be increased.

The present invention has been completed based on the above findings.
In one embodiment, based on the total solid content, (1) containing titania as a white pigment in an amount of 5 to 60% by mass, and (2) a fluorescent pigment having an emission spectrum peak at 480 to 620 nm in an amount of 0.10 to 10% by mass, 0.10 to 10% by mass of a fluorescent pigment that emits light having a wavelength of excitation spectrum of 420 to 450 nm and a higher visibility than mercury rays, and a total of 0.20 to 20% by mass of these fluorescent pigments This is a highly reflective paint for fluorescent lamp reflectors.

  In another embodiment, the present invention provides a fluorescent pigment containing titania as a white pigment in an amount of 5 to 60% by mass and having an emission spectrum peak at 480 to 620 nm of 0.10 to 10% by mass, and an excitation spectrum peak. Is characterized by containing 0.10 to 10% by mass of a fluorescent pigment that emits light having a wavelength of 420 to 450 nm and a higher visibility than mercury rays, and a total of 0.20 to 20% by mass of these fluorescent pigments, It is a highly reflective coated metal plate for fluorescent lamp reflectors.

  According to the present invention, it is possible to provide a paint and a coated metal plate that is an object to be coated that can efficiently improve reflectivity as a reflector of a lighting fixture by using the visibility characteristics of human eyes. .

  First, the highly reflective paint of the present invention will be described. In the following description, the content of each component in the paint is mass% based on the total solid content of the paint, and the content of each paint component on the basis of the solid content is substantially contained in the coating film. It is the same as the amount.

  The highly reflective paint of the present invention contains 5 to 60% titania (titanium oxide). Titania is a highly concealing pigment and can impart high reflectivity to the coating film. When the content is less than 5% by mass, the concealability is insufficient, and when it exceeds 60%, the pigment is too much and the bending workability of the film is deteriorated.

  Titania may be either a rutile type or an anatase type. Further, titania whose surface is coated with Al2O3, SiO2, ZnO or the like, or titania pigment combined with calcium sulfate, magnesium sulfate, barium sulfate or the like can be used.

The highly reflective paint of the present invention further contains the following fluorescent pigments (a) and (b):
(a) a fluorescent pigment having an emission spectrum peak at 480 to 620 nm,
(b) A fluorescent pigment having an excitation spectrum peak at 420 to 450 nm.

  As described above, the fluorescent pigment (a) can convert incident light having a lower visibility and lower wavelength into light in the vicinity of 555 nm, which is the peak of visibility. The fluorescent pigment (b) can convert a strong (high energy) mercury beam emitted from a fluorescent lamp into light with higher visibility. Any of the fluorescent pigments is effective in improving reflectivity from the viewpoint of the visibility of the human eye.

  In order to obtain a highly reflective paint, the fluorescent pigments (a) and (b) may be contained. Some fluorescent pigments satisfy both the above requirements (a) and (b), and may be used. Of course, both of the fluorescent pigments (a) and (b) may be contained. In particular, when used for a reflector of a fluorescent lamp, this further improves the reflectivity. When used for a reflector of an incandescent lamp other than a fluorescent lamp, it is preferable to use the fluorescent pigment (a), but the fluorescent pigment (b) can improve the reflectivity. .

  The content of the fluorescent pigment in the paint (the total amount when two or more are used) is in the range of 0.05 to 20%. When the content of the fluorescent pigment is less than 0.05%, the effect of improving the reflectivity by the fluorescent pigment is insufficient. On the other hand, when the fluorescent pigment exceeds 20%, the reflectivity may be lowered. This is because the fluorescent pigment has an absorption spectrum in addition to the excitation spectrum, so that a part of the irradiation light is absorbed. A preferable content of the fluorescent pigment is in the range of 0.1 to 15%.

The total amount of pigment, that is, the total amount of titania (white) pigment and fluorescent pigment (other pigments if present) is preferably not more than 80%.
The highly reflective paint of the present invention may contain other pigments in addition to the titania and the fluorescent pigment. Examples of other pigments include white pigments other than titania, colored pigments, and rust preventive pigments. By adding a coloring pigment, the paint can be toned to an arbitrary color.

  In general, since the fluorescent pigment is an organic substance and is inferior in light resistance, it is preferable to add an appropriate ultraviolet absorber or radical scavenger to the coating material of the present invention. In addition, various additives conventionally used in paints, for example, a smoothing agent, an antifoaming agent, a dispersing agent and the like can be added as desired.

  The film forming component (binder) of the paint is not particularly limited. It may be a general organic resin or an inorganic material. Typical organic resins include polyester resins, urethane resins, acrylic resins, epoxy resins, fluororesins, melamine resins, and the like.

  When the above highly reflective paint is applied to a suitable substrate and the coating film is appropriately dried or baked, high reflectivity can be imparted to the substrate surface. As a base material, not only the metal plate mentioned later but arbitrary materials can be used. For example, resin, ceramic, cloth, wood, paper, etc. can be used as the base material. When using any of these substrates for lighting covers, applying the paint of the present invention to the substrate surface on the side directed to the light source to form a highly reflective film, even with the same light source, It becomes a lighting fixture with high appliance efficiency that can be felt bright.

  The highly reflective coated metal plate of the present invention is produced by coating the above-mentioned paint on a metal plate and baking it as necessary. The thickness of the formed highly reflective coating film is preferably in the range of 5 to 100 μm. If the coating film is too thin, the concealability and reflectivity are insufficient, and if the coating film is too thick, the workability is lowered. The coating may be performed on one side or both sides of the substrate.

  The coating can be performed by various methods commonly used for coating a metal plate (eg, roll coating, curtain flow coating, spray coating, dipping, bar coating, brush coating, etc.). The baking conditions are set according to the binder or organic resin used, and those skilled in the art can easily set the baking conditions.

  Examples of the metal plate serving as the substrate include, but are not limited to, a steel plate, a plated steel plate, an aluminum plate, a titanium plate, and the like. Examples of the plated steel sheet include zinc or zinc alloy plated steel sheet, aluminum or aluminum alloy plated steel sheet, and tin plated steel sheet. The steel plate includes a stainless steel plate and other alloy steel plates.

  Before applying the highly reflective paint of the present invention, for the purpose of improving coating film adhesion, rust prevention, paint finish, etc., the substrate metal plate is subjected to undercoating, undercoating (primer), intermediate coating, etc. It is also possible to apply. These may be carried out according to the prior art. Moreover, after applying the paint of the present invention, a transparent protective film such as a clear film may be formed.

  The painted metal plate of the present invention exhibits a high reflectance in the vicinity of 555 nm where human visibility is high. Therefore, it is particularly useful as a reflector for various lighting fixtures (eg, fluorescent lamps, mercury lamps, incandescent lamps, etc.), and in particular, for a fluorescent lamp reflector, thereby increasing the brightness of the lighting fixtures and increasing the fixture efficiency. .

(Preparation of highly reflective paint)
The following three types of pigments were prepared.
(1) White pigment: Titania pigment made by Ishihara Sangyo, typake "CR-50";
(2) Fluorescent pigment A: “VR-17” manufactured by DayGlo having an excitation spectrum peak near 460 nm and an emission spectrum peak near 520 nm,
(3) Fluorescent pigment B: “VR-18” manufactured by DayGlo having an excitation spectrum peak near 450 nm and an emission spectrum peak near 510 nm.

Of the above two types of fluorescent pigments,
Fluorescent pigment A is “a fluorescent pigment having an emission spectrum peak at 480 to 620 nm”
Fluorescent pigment B is a “fluorescent pigment having an emission spectrum peak at 480 to 620 nm”
And “a fluorescent pigment having an excitation spectrum peak of 420 to 450 nm”.

  Based on the total solid content, baking paints were prepared containing a constant white pigment titania of 40% and containing one or both of the fluorescent pigments in various amounts as shown in Table 1. The balance of the solid content of the paint is the polyester resin of the binder and the melamine crosslinking agent. An appropriate amount of cyclohexanone was used as the solvent. A reflective paint was obtained by dispersing and mixing these components using a ball mill.

(Preparation of painted metal plate)
As the substrate, a hot dip galvanized steel sheet defined in JIS-G3302 using a cold rolled steel sheet having a thickness of 0.8 mm as a base material was used. One side of this substrate was roll-coated with the above-mentioned paints in an amount to give a dry film thickness of 30 μm, and baked at 230 ° C. for 60 seconds to obtain a reflective coated metal plate.

  The reflection spectrum of the painted surface of the obtained coated metal plate is irradiated with light from a commercially available fluorescent lamp on the painted surface, and the reflected light and fluorescence emitted from the painted surface are collected using an integrating sphere, and fluorescent light manufactured by Shimadzu Corporation is collected. Measurement was performed using a spectrophotometer.

  As an index for evaluating reflectivity, the reflectance is the ratio of the intensity of the white fluorescent lamp at 555 nm, which is the peak of visibility, and the intensity of reflection from the sample. The reflectance is 90% or more. Evaluated to be excellent in reflectivity. The reflectance results are also shown in Table 1.

  As can be seen from Table 1, when the paint further containing the fluorescent pigment according to the present invention is used in comparison with the paint of Comparative Example 1 containing only titania as the pigment, the produced coated metal plate has a visual sensitivity. The reflectance at the peak of 555 nm is improved. In particular, when the fluorescent pigment A and the fluorescent pigment B are added in combination, a coated metal plate having a further improved reflectance is obtained. As shown in Example 2, depending on the amount of the two types of fluorescent pigments added, it is close to 100%. Excellent reflectivity was achieved. However, when the amount of the fluorescent pigment added is too small or too large, the reflectivity is lowered.

  In FIG. 1, the irradiation spectrum of the used white fluorescent lamp and the reflection spectrum of the comparative example 1 and the reference example 3 are shown. From FIG. 1, it can be seen that the reflection spectrum of Comparative Example 1 is substantially the same as the irradiation spectrum of the irradiated white fluorescent lamp on the longer wavelength side than 410 nm. That is, it can be seen that titania increases the reflectivity almost uniformly over almost all wavelengths in the visible range.

  On the other hand, in the film of Example 3, the reflection spectrum in the region of 410 to 490 nm, particularly in the region of 445 to 490 nm is shifted to 490 to 570 nm. Thus, since the reflection spectrum in the wavelength range with low visibility shifts to a wavelength range close to 555 nm, which is the peak in visibility, the reflectance at 555 nm contains only titania as shown in Table 1. Compared with the film of Comparative Example 1 to be greatly improved. As a result, when the coated metal plate of the present invention is used for a lighting fixture, particularly a reflector for a fluorescent lamp, the lighting fixture can feel brighter than that of Comparative Example 1.

The irradiation spectrum of a white fluorescent lamp and the reflection spectra of Comparative Example 1 and Reference Example 3 are shown.

Claims (2)

Based on total solids
(1) containing titania as a white pigment in an amount of 5 to 60% by mass, and
(2) 0.10-10% by mass of fluorescent pigment with emission spectrum peak in the range of 480-620 nm, 0.10% of fluorescent pigment emitting light having a wavelength of excitation spectrum of 420-450 nm and higher visibility than mercury rays ~ 10 mass%, and a total of 0.20-20 mass% of these fluorescent pigments,
A highly reflective paint for fluorescent lamp reflectors.  A white pigment containing titania in an amount of 5 to 60% by mass, a fluorescent pigment having an emission spectrum peak of 480 to 620 nm, 0.10 to 10% by mass, an excitation spectrum peak of 420 to 450 nm, and a mercury line A highly reflective coating metal for a fluorescent lamp reflector, comprising 0.10 to 10% by mass of a fluorescent pigment that emits light having a wavelength with higher visibility, and a total of 0.20 to 20% by mass of these fluorescent pigments Board.

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